This design incorporates features such as digital audio processing, equalization and firmware management to assist in the development of differentiated Lightning based headphones, headsets and audio adapters.
Tempo Semiconductor has introduced the TDTSI017 which is a reference design that makes it easy for manufacturers to develop Apple Lighting based headphones, headsets and female 3.5mm audio adapters. The design has been developed to make it easy for the development of digital audio accessories through a ready-to-use hardware and software platform. The design is based on Tempo’s LAM (Lightning Audio Module) architecture and Apple MFi certified hence enabling manufacturers to design audio accessories that can work with it without having to build all the necessary hardware and firmware from scratch.
TDTSI017 is configurable in several ways, such that there are models that either come equipped with built-in charging or lack that functionality. Different manufacturers have the option to select between the two connector choices – female Lightning and USB. Another configuration available on this platform includes those models that have the FM and RDS digital tuner functionality included or not. The pre-configured TSCT8x Audio Hub Controller from Tempo is an important element of the Lightning platform design that minimizes the necessity of developing the microcontroller firmware code.
Audio customisation is another important aspect of the reference design. Tempo provides its Windows-based Audio System Configuration (ASC) graphical user interface (GUI), which enables acoustic engineers to generate digital signal processing (DSP) tuning files for specific headphone designs. Engineers can configure equalisation characteristics according to their desired sound profile. The tool also includes an automatic inverse equalisation function that generates an EQ curve from a customer-defined sound pressure level (SPL) target. This helps engineers achieve a flatter frequency response and optimise the acoustic characteristics of their products without developing DSP algorithms independently. The generated tuning files can be incorporated into the TSCT8x firmware image.
The design also takes care of firmware management and customization through the TempoSound app from Tempo, which is an iOS application. Its default feature provides firmware update capability for Lightning accessories that are MFi-certified through firmware that is available in the cloud. It thus reduces the burden on the manufacturer’s side with respect to software development and maintenance. Further, it provides capabilities for advanced audio customization with 12-band graphic equalizer and 12-band parametric equalizer.
For the benefit of design engineers, Tempo has designed the TDTSI017 reference design files that include the circuit schematic, BOM list and PCB layout in four layers. These files are designed keeping in mind the RoHS, WEEE, CE, FCC and DfM compliance. There is also a demo board that can be tested as well as access to its ASC tuning tool. These TDTSI017 Rev E design files and demo board are accessible by any of the Apple MFi licensees in good standing under a mutual non-disclosure agreement (NDA).
For more information, click here.
